Shore birds dying on fishers' hooks

Up to 1500 black petrels could have been killed in the Hauraki Gulf every year between 2003 and 2009. Photo / Supplied

Shorebird species in the Hauraki Gulf and around New Zealand are being pushed to the edge of extinction as they are caught in fishing lines and nets.

A Ministry of Fisheries report says population decline in as many as 21 separate species may be affecting their ability to reach sustainable population levels.

Forest and Bird says up to 1500 black petrels could have been killed in the Hauraki Gulf every year between 2003 and 2009, a death rate estimated as 10 times higher than the population can sustain. Most are caught in the snapper fishery where long, baited lines are laid along the seabed.

Black petrels, classified as vulnerable, breed only on Great Barrier and Little Barrier Islands.

Other birds at risk include the critically endangered Chatham albatross, the Westland petrel and flesh-footed shearwater.

Forest and Bird spokes-woman Karen Baird said the fishing industry killed about 30,000 seabirds every year, and continued commercial fishing wasn't sustainable if critically endangered species were still being driven towards extinction.

The Ministry of Fisheries says New Zealand fishing methods known to kill seabirds include long fishing lines in the open sea, sea-bottom longlining, inshore and deepwater trawling and set-netting.

All inshore bottom longline vessels over 7m are required to use brightly-coloured streamer lines to scare the birds away. Lines are supposed to be set at night when birds can't see them or weighted down, so birds can't reach the hooks.

Regulatory manager Tom Chatterton said the ministry would try to measure whether birds' lives were being saved by measures like the coloured streamers. Officials would focus on areas where shorebirds foraged for food and fishing boats operated.

Chatterton said it was hard to work out how many birds were killed and Forest and Bird estimates were based on unreliable risk assessments.